This is an application for a Mentored Clinical Scientist Research Career Development Award (K08) for Dr. Bennett Penn, a third-year fellow Division of Infectious Diseases with pending appointment as Professor of Medicine (adjunct series) at UCSF. His long-term goal is to determine the molecular mechanisms by which M. tuberculosis causes human disease and to develop new therapeutics based on this information. The specific goal of this application is to use a combination of mass spectrometry (MS) and genetic approaches to identify the functionally important human proteins targeted by M. tuberculosis virulence factors, and to obtain the necessary additional training for Dr. Penn to lead his own research group. In his preliminary studies, he has used affinity purification and mass spectrometry (MS) to identify several hundred novel protein-protein interactions between M. tuberculosis and human cells. In Aim 1, he will use a set of bioinformatics and biochemical approaches to refine and validate these MS findings. In Aim 2, he will use genetic approaches to determine which of these interactions play functionally important roles during M. tuberculosis infection. In Aim 3, a select number of these interactions will be subjected to detailed biochemical analysis to establish the molecular mechanisms by which they factors disrupt host immune function. Dr. Penn has assembled a team of three co-mentors that bridge several disciplines to guide his continued advancement. Importantly, since Dr. Penn's doctoral work was in the field of mammalian developmental biology, the K08 award will provide a period of additional research training to acquire the specialized skills for manipulating virulent M. tuberculosis, and carrying out MS experiments. The K08 will also provide added support for acquiring the skills to manage an independent research group through focused courses and seminars offered by UCSF, and will permit Dr. Penn to maintain his clinical specialization by working at the SFGH TB Clinic. By the completion of this award Dr. Penn will be in an excellent position lead his own research group and to submit an R01 that further extends his studies on host-pathogen interactions in TB. RELEVANCE: This project is relevant to human health because understanding how Mycobacterium tuberculosis disrupts the immune system will lay the foundation for developing therapies aimed at restoring these functions and thereby improving therapy for tuberculosis.